Does metformin improve the efficacy of standard epidermal growth factor receptor-tyrosine kinase inhibitor treatment for patients with advanced non-small-cell lung cancer?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether metformin improved the efficacy of standard epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment for patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer. A total of 99 papers were found using the reported search, of which 4 represented the best evidence to answer this clinical question. The authors, journal, publication date, country, study type, treatment regimen, relevant outcomes and results of these papers are tabulated. We concluded that the addition of metformin to EGFR-TKI might improve the survival of patients with EGFR-mutated non-small-cell lung cancer and diabetes mellitus type 2. However, for non-diabetic non-small-cell lung cancer patients with EGFR mutation, the efficiency of additional metformin in EGFR-TKI treatment remains unclear because of the conflicting results of only 2 available studies.